The present invention relates to diagnostics of structures, and more particularly to diagnostic network patch (DNP) systems for monitoring structural conditions.
In general, structures in service may require periodic inspections and appropriate maintenance services to prolong their life and/or to prevent catastrophic failures. Numerous methods have been employed to identify fault or damage of structures, where these methods may include conventional visual inspection and non-destructive techniques, such as ultrasonic and eddy current scanning, acoustic emission and X-ray inspection. These conventional methods require at least temporary removal of structures from service for inspection. Although still used for inspection of isolated locations, they are time-consuming and expensive.
With the advance of sensor technologies, several diagnostic systems for in-situ structural integrity monitoring have been in progress. Typically, these diagnostic systems may utilize a number of sensory devices that are built in host structures and operate as sensors. As the sensors merely receive diagnostic signals propagating through the structures, the diagnostic systems are referred to as passive systems. Such passive diagnostic systems have difficulties in regional monitoring and adaptive self sensing. The active systems disclosed in U.S. patent applications, Ser. No. 10/942,714, filed on Sept. 16, 2004 and issued as U.S. Pat. No. 7,286,964, Ser. No. 10/942,366, filed on Sept. 16, 2004 and issued as U.S. Pat. No. 7,117,742, Ser. No. 11/304,441, filed on Dec. 14, 2005, and abandoned, Ser. No. 11/397,351, filed on Apr. 3, 2006 and issued as U.S. Pat. No. 7,281,428, Ser. No 11/414,166, filed on Apr. 27, 2006 and issued as U.S. Pat. No. 7,197,931, Ser. No 11/445,452, filed on Jun. 2, 2006 and issued as U.S. Pat. No. 7,246,521, Ser. No 11/502,127, filed on Aug. 9, 2006 and issued as U.S. Pat. No. 7,325,456, and Ser. No. 11/502,319, filed on Aug. 9, 2006 and issued as U.S. Pat. No. 7,322,244, which are incorporated herein by reference in their entirety, may provide enhanced capabilities in regional monitoring and self sensing. In the active systems, one or more of the sensors may generate diagnostic signals that propagate through the host structure, while others may develop sensor signals in response to the diagnostic signals. Hereinafter, the terms patch, sensor, and actuator are used interchangeably as a patch may have capabilities to transmit and/or sense the signals.
As the number of patches in the active systems has increased, the complexity in arranging and operating the patches also has increased. As such, there is a need for a new approach in networking the patches to optimize the use of the patches and to enhance the efficiency and accuracy of the diagnostic system.